In order to provide effective shielding of a bundle of electrical cables against electromagnetic interference it is necessary to ensure that the shield has electrical continuity and that connection to ground is of low resistance. Where there is to be a transition in the cabling run for dividing or branching the bundle into two or more smaller bundles, it is normal to interrupt the shield and insert a solid, usually metal, branching fitting to which the individual shields of the main and branch bundles are each attached to maintain continuity of shielding. A ground-bonding connection is usually made directly to the branching fitting.
The use of solid fittings as referred to above for cable-branching transitions has disadvantages in that they add weight and bulk to the cabling and increase costs. It is an object of the present invention to provide electrical-cable branching-transitions, and methods for providing such transitions, for which shielding against electromagnetic interference is maintained and the above disadvantages are, at least to a significant extent, overcome.
According to one aspect of the invention there is provided a method of providing an electrical-cable transition at which a shielded bundle of cables of a cabling run is divided into two or more shielded branch-bundles, wherein continuity of shielding of the cabling run against electromagnetic interference is maintained through the transition by wrapping a flexible shielding element round the branch bundles and the main bundle (that is to say, the bundle from which the branch bundles are divided) to envelop them all together at the transition as one and overlap, or be overlapped by, shielding of each of the branch bundles, and establishing electrical interconnection of the flexible shielding element with the shielding of the individual branch bundles.
According to another aspect of the invention there is provided an electrical-cable transition at which a shielded bundle of cables of a cabling run is divided into two or more individually-shielded branch-bundles, comprising a flexible shielding element wrapped round the branch bundles and the main bundle (that is to say, the bundle from which the branch bundles are divided) to envelop them all together as one at the transition and overlap, or be overlapped by, shielding of each of the branch bundles, and wherein the flexible shielding element is electrically interconnected with the shielding of the branch bundles for maintaining continuity through the transition of shielding of the cabling run against electromagnetic interference.